java 文件上传下载

 

文件下载

 

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.Iterator;

import java.util.List;

 

import javax.servlet.ServletException;

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import org.apache.commons.fileupload.FileItem;

import org.apache.commons.fileupload.FileUploadException;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

 

 

/**

 * 文件下载处理Servlet

 * 

 */

public class FileDownloadServlet extends HttpServlet {

 

private int maxPostSize = 100 * 1024 * 1024;

protected void doGet(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

doPost(request, response);

}

 

protected void doPost(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

 

System.out.println("Access FileDownloadServlet");

// 获取访问路径

String webPath ="D:/tomcat"

String downloadPath = webPath + "\\webapps\\pages\\dbdata\\download\\";

// 检查存储目录是否已经存在，如果不存在则需要创建存储目录

File filePath = new File(downloadPath);

if (!filePath.exists()) {

filePath.mkdirs();

}

//设置客户端保存时指定默认文件名

//String fileName = "test.xml";

String fileName = request.getAttribute("file").toString();

String path = downloadPath + fileName;

System.out.println(path);

// 写流文件到前端浏览器

ServletOutputStream out = response.getOutputStream();

response.setHeader(" Content-disposition ", " attachment;filename= " + fileName);

BufferedInputStream bis = null;

BufferedOutputStream bos = null;

try {

bis = new BufferedInputStream(new FileInputStream(path));

bos = new BufferedOutputStream(out);

byte[] buff = new byte[2048];

int bytesRead;

while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {

bos.write(buff, 0, bytesRead);

}

} catch (IOException e) {

throw e;

} finally {

if (bis != null)

bis.close();

if (bos != null)

bos.close();

}

response.flushBuffer();

}

 

}

 

 

文件上传

 

 

 

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.PrintWriter;

import java.util.Iterator;

import java.util.List;

import java.util.Properties;

 

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import org.apache.commons.fileupload.FileItem;

import org.apache.commons.fileupload.FileUploadException;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

 

 

/**

 * 文件上传处理Servlet

 *

 */

public class FileUploadServlet extends HttpServlet {

private int maxPostSize = 100 * 1024 * 1024;

private String fileName; // 上传的文件名称

public String getFileName() {

return fileName;

}

 

public void setFileName(String fileName) {

this.fileName = fileName;

}

 

protected void doGet(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

doPost(request, response);

}

 

protected void doPost(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

// 获取访问路径

String uploadPath = webPath + "\\webapps\\pages\\dbdata\\upload\\";

// 检查存储目录是否已经存在，如果不存在则需要创建存储目录

File filePath = new File(uploadPath);

if (!filePath.exists()) {

filePath.mkdirs();

}

response.setContentType("text/html;charset=UTF-8");

request.setCharacterEncoding("UTF-8");

PrintWriter out = response.getWriter();

DiskFileItemFactory factory = new DiskFileItemFactory();

factory.setSizeThreshold(1024 * 10);

ServletFileUpload upload = new ServletFileUpload(factory);

upload.setSizeMax(maxPostSize);

// 上传文件

try {

List fileItems = upload.parseRequest(request);

Iterator iter = fileItems.iterator();

while (iter.hasNext()) {

FileItem item = (FileItem) iter.next();

if (!item.isFormField()) {

String fileName = item.getName();

this.setFileName(fileName); //保存文件名称

try {

System.out.println("上传的文件是：" + uploadPath + fileName);

File skFile = new File(uploadPath + fileName);

if (skFile.exists()) {

skFile.delete();

item.write(new File(uploadPath + fileName));

} else {

item.write(new File(uploadPath + fileName));

}

} catch (Exception e) {

e.printStackTrace();

}

}

}

} catch (FileUploadException e) {

e.printStackTrace();

}

 

}

}

 

JSP

 

<!--1 必须是post提交
    2 表单的编码类型必须指定为 enctype="multipart/form-data" -->
<form action="/upload?cmd=upload" method="post" enctype="multipart/form-data">
    用户名:<input type="text" name="username"><br/>
    图像:<input type="file" name="file"><br/>
    <input type="submit" value="提交">
</form>